Association of HSD3B1 Genotype With Response to Androgen-Deprivation Therapy for Biochemical Recurrence After Radiotherapy for Localized Prostate Cancer.

IMPORTANCE: The variant HSD3B1 (1245C) allele enhances dihydrotestosterone synthesis and predicts resistance to androgen-deprivation therapy (ADT) for biochemically recurrent prostate cancer after prostatectomy and for metastatic disease. Whether this is true after radiotherapy is unknown. OBJECTIVE: To determine whether the HSD3B1 (1245C) allele predicts worse clinical outcomes from ADT for biochemical recurrence after radiotherapy. DESIGN, SETTING, AND PARTICIPANTS: The Prostate Clinical Research Information System at Dana-Farber Cancer Institute was used to identify the study cohort, which included men treated with ADT for biochemical recurrence after primary radiotherapy between 1996 and 2013. We retrospectively determined HSD3B1 genotype. MAIN OUTCOMES AND MEASURES: Time to progression, time to metastasis, and overall survival according to genotype. Demographic and treatment characteristics were evaluated for confounders. Multivariable analyses were performed to adjust for known prognostic factors. RESULTS: A total of 218 eligible men were identified, of whom 213 (98%) were successfully genotyped. Of these, 97 of 213 (46%), 96 of 213 (45%) and 20 of 213 (9%) carried 0, 1, and 2 variant alleles. Overall variant allele frequency was 136 of 426 alleles (32%). Median patient age (interquartile range) was 69 (63-74), 72 (65-78), and 69 (65-77) years for 0, 1, and 2 variant alleles (P = .03). Demographic and treatment factors were otherwise similar. During a median follow-up of 7.9 years, median time to progression was 2.3 years (95% CI, 1.6-3.1 years) with 0 variant alleles, 2.3 years (95% CI, 1.5-3.3 years) with 1 variant allele, and 1.4 years (95% CI, 0.7-3.3 years) with 2 variant alleles (P = .68). Median time to metastasis diminished with the number of variant alleles inherited: 7.4 (95% CI, 6.7-9.7), 5.8 (95% CI, 4.9-6.5), and 4.4 (95% CI, 3.0-5.7) years, with inheritance of 0, 1, and 2 variant alleles, respectively (P = .03). Median OS was 7.7 (95% CI, 6.7-10.3), 6.9 (95% CI, 5.8-8.4), and 7.2 (95% CI, 3.8-7.9) years with inheritance of 0, 1, and 2 variant alleles, respectively (P = .31). On multivariable analysis with 0 variant alleles as the reference, the adjusted hazard ratio for metastasis was 1.19 (95% CI, 0.74-1.92) (P = .48) for 1 variant allele and 2.01 (95% CI, 1.02-3.97) (P = .045) for 2 variant alleles. Multivariable analysis did not demonstrate significant differences in TTP or OS. CONCLUSIONS AND RELEVANCE: In this study, the HSD3B1 (1245C) allele was associated with more rapid development of metastases in men treated with ADT for biochemical recurrence after primary radiation therapy for prostate cancer. Notably, 105 of 213 men (49%) had received prior ADT, and 119 of 213 (56%) received an androgen receptor antagonist during salvage treatment, both of which may attenuate the effect of the variant allele.

Scalable whole-exome sequencing of cell-free DNA reveals high concordance with metastatic tumors.

Whole-exome sequencing of cell-free DNA (cfDNA) could enable comprehensive profiling of tumors from blood but the genome-wide concordance between cfDNA and tumor biopsies is uncertain. Here we report ichorCNA, software that quantifies tumor content in cfDNA from 0.1× coverage whole-genome sequencing data without prior knowledge of tumor mutations. We apply ichorCNA to 1439 blood samples from 520 patients with metastatic prostate or breast cancers. In the earliest tested sample for each patient, 34% of patients have ≥10% tumor-derived cfDNA, sufficient for standard coverage whole-exome sequencing. Using whole-exome sequencing, we validate the concordance of clonal somatic mutations (88%), copy number alterations (80%), mutational signatures, and neoantigens between cfDNA and matched tumor biopsies from 41 patients with ≥10% cfDNA tumor content. In summary, we provide methods to identify patients eligible for comprehensive cfDNA profiling, revealing its applicability to many patients, and demonstrate high concordance of cfDNA and metastatic tumor whole-exome sequencing.

The impact of statin use on the efficacy of abiraterone acetate in patients with castration-resistant prostate cancer.

BACKGROUND: Statins compete with DHEAS for influx through the SLCO2B1 transporter, which may prolong time to progression (TTP) on androgen deprivation therapy. Abiraterone acetate (AA) may also undergo SLCO-mediated transport. Based on preclinical findings showing antagonism, we hypothesized that statins may compete with AA for influx via SLCO2B1 and could negatively impact drug efficacy. METHODS: We queried two institutional clinical databases (Dana-Farber Cancer Institute [DFCI], Johns Hopkins University [JHU]) for CRPC patients treated with AA. Treatment duration was a surrogate for TTP. Associations between statin use and AA duration were estimated using the Kaplan-Meier method. Multivariable Cox regression modeling adjusted for known prognostic factors. RESULTS: Of the 224 DFCI and 270 JHU patients included, the majority (96%) had metastatic disease. Nearly half (41% and 45%) were statin users. In the DFCI cohort, there was a trend toward longer AA duration in statin users: 14.2 versus 9.2 months (HR 0.79, 95%CI: 0.57-1.09, P = 0.14). There was no association between statin use and AA duration in the JHU cohort: 8.3 versus 8.0 months (HR 0.89, 95%CI: 0.69-1.16, P = 0.38) in the statin users versus non-users, except for a trend in patients that had not previously received docetaxel or enzalutamide (HR 0.79; 95%CI: 0.57-1.10). CONCLUSIONS: Contrary to our initial hypothesis, there was a trend toward longer (rather than shorter) AA duration in statin users in the entire DFCI cohort and in the enzalutamide- and docetaxel-naïve JHU patients. Together, these results do not support the hypothesis that statins interfere with AA efficacy.

Association of AR-V7 and Prostate-Specific Antigen RNA Levels in Blood with Efficacy of Abiraterone Acetate and Enzalutamide Treatment in Men with Prostate Cancer.

PURPOSE: We evaluated the association of PSA and androgen receptor splice variant-7 (AR-V7) transcript levels in patients' blood with time to treatment failure (TTF) and overall survival (OS) with abiraterone acetate and/or enzalutamide treatment in castration-resistant prostate cancer (CRPC) patients. EXPERIMENTAL DESIGN: RNA levels of AR-V7 and PSA in peripheral blood collected before treatment were quantified using droplet digital-PCR in retrospective cohorts treated with abiraterone acetate (N = 81) or enzalutamide (N = 51) for CRPC. Multivariable Cox regression adjusted for known prognostic factors was used for analyses. RESULTS: PSA transcripts were detected in 57% of abiraterone acetate-treated patients and in 63% of enzalutamide-treated patients. PSA-positive patients had a shorter TTF than PSA-negative patients [adjusted HR = 2.27 (95% confidence interval (CI) 1.26-4.10) and 2.60 (95% CI, 1.19-5.69); P = 0.006 and 0.017 in abiraterone acetate and enzalutamide cohorts, respectively]. Patients with a higher-AR-V7 transcript level had a shorter TTF with abiraterone acetate and enzalutamide in univariate analysis (median 8.0 months vs. 15.6 months, P = 0.046 in abiraterone acetate-cohort and 3.6 months vs. 5.6 months; P = 0.050 in enzalutamide cohort). In multivariable models, the association with TTF remained significant in the enzalutamide cohort (adjusted HR = 2.02; 95% CI, 1.01-4.05; P = 0.048), but statistically insignificant in the abiraterone acetate cohort. In both cohorts, we observed potential prognostic value of both PSA and AR-V7 RNA expression on OS; patients with detectable PSA transcripts and high AR-V7 predicted the poorest OS. CONCLUSIONS: PSA and AR-V7 transcripts in blood potentially serve as biomarkers predicting TTF and OS with abiraterone acetate or enzalutamide treatment. If validated prospectively, their detection could be facilitated without isolation of circulating tumor cells. Clin Cancer Res; 23(3); 726-34. ©2016 AACR.

A Genetic Variation of SOD2 Does Not Determine Duration of Response to Androgen Deprivation Therapy for Prostate Cancer.

BACKGROUND: Silencing SOD2 expression upregulates androgen receptor (AR) signaling and expression of SOD2 is downregulated in CRPC, compared with untreated tumors. The decreased SOD2 activity could lead to AR gain-of-function and the development of castration-resistance. METHODS: We genotyped SOD2-rs4880 in a cohort of 753 prostate cancer patients receiving androgen deprivation therapy (ADT) between 1996 and 2010. The rs4880 encodes Ala16Val in SOD2 and the Val variant has been demonstrated to be functionally less efficient than the Ala variant. We assessed the impact of SOD2-rs4880 variants on the time to progression (TTP) and overall survival (OS) on ADT using multivariable Cox regression. RESULTS: Four hundred thirty-two out of 753 (57%) had metastases at the time of ADT initiation. Overall, median TTP on ADT was 18.4 (95%CI: 15.8, 20.9) months and median overall survival (OS) from ADT initiation was 6.3 (95%CI: 5.8, 6.8) years. In unadjusted and adjusted analyses, there was no association between SOD-rs4880 and TTP or OS on ADT (P > 0.05). Results were similarly negative among patients with and without metastatic disease at ADT initiation. CONCLUSIONS: Our result suggests that a functional genetic variant in SOD2 does not determine the efficacy of ADT for prostate cancer. It is possible that the drastic downregulation of SOD2 in advanced prostate cancer cells may have overridden any influence of the genetic variation of SOD2. This study suggests the need for careful consideration about timing if the application of SOD2 mimetics for prostate cancer therapy is considered. Prostate 76:1338-1341, 2016. © 2016 Wiley Periodicals, Inc.

Duration of Androgen Deprivation Therapy for High-Risk Prostate Cancer: Application of Randomized Trial Data in a Tertiary Referral Cancer Center.

INTRODUCTION: We evaluated the incidence and predictors of the use of long-term (2-3 years) versus shorter term androgen deprivation therapy (ADT) in radiation-managed men with high-risk prostate cancer. PATIENTS AND METHODS: We identified 302 patients from the Dana-Farber Cancer Institute patient registry who had been diagnosed with high-risk prostate cancer (T3a or prostate-specific antigen [PSA] > 20 ng/mL or Gleason score 8-10) from 1993 to 2015. We assessed the intended duration of ADT and used multivariable Cox regression to evaluate the predictors of receiving a shorter course of ADT than recommended by the guidelines (< 2 years). RESULTS: The course of ADT intended by physicians increased after the 2008/2009 publication of trials showing the superiority of long-term versus short-term ADT, with 43.5% intending ≥ 2 years before versus 61.4% after (P = .014). Starting in 2010, 49.4% of patients actually received < 2 years of ADT. The most common reasons for receipt of shorter course ADT were intolerance of ADT side effects, patient comorbidity/age, the presence of T3a on magnetic resonance imaging only as the sole high-risk feature, or participation in a clinical trial. Moderate to severe comorbidity assessed using the Adult Comorbidity Evaluation-27 (adjusted hazard ratio [AHR] = 2.94), Gleason score < 8 (AHR = 5.66), and PSA < 20 ng/mL (AHR = 4.19) all predicted for receipt of shorter course ADT (P < .05 for all). CONCLUSION: In a tertiary-care setting, the rates of long-course ADT for high-risk disease have increased since the 2008/2009 trials supporting its use. However, approximately one half of patients continued to receive shorter course ADT, often because of intolerance of side effects, underlying comorbidity, or physician judgment about the aggressiveness of the disease.

Association of SLCO2B1 Genotypes With Time to Progression and Overall Survival in Patients Receiving Androgen-Deprivation Therapy for Prostate Cancer.

PURPOSE: To validate the association of three previously demonstrated SLCO2B1 germline variants with time to progression (TTP) in patients receiving androgen-deprivation therapy (ADT), and to evaluate if the SLCO2B1 genetic variants impacted overall survival (OS) for prostate cancer (PC). PATIENTS AND METHODS: Three single nucleotide polymorphisms (SNPs), exonic SNP rs12422149 and intronic SNPs rs1789693 and rs1077858, were genotyped in an independent validation cohort of 616 patients with PC who were treated with ADT at the Dana-Farber Cancer Institute from 1996 to 2013. Multivariable Cox proportional hazards regression adjusting for known prognostic factors estimated the association of these genetic variants with TTP and OS in patients receiving ADT. The expression of SLCO2B1 was examined in prostatectomy samples, and the impact of SLCO2B1 expression level on DHEAS (dehydroepiandrosterone sulfate) uptake was evaluated in cell lines. RESULTS: The association between exonic SNP rs12422149 and TTP in patients treated with ADT was confirmed in univariable (P = .019) and multivariable analyses (adjusted hazard ratio, 1.31; 95% CI, 1.00 to 1.72 for GG v AA/AG; P = .049). Because OS had not been previously evaluated, we examined the association in the combined initial and validation cohorts (N = 1,094). The intronic SNP rs1077858 was associated with OS in both univariable (P = .009; Bonferroni's method adjusted P = .027) and multivariable analyses (adjusted hazard ratio, 1.35; 95% CI, 1.07 to 1.71 for GG v AA/AG; P = .012). SLCO2B1 expression in normal prostate tissue and in 22RV1 cells carrying the major allele of SNP rs1077858 was significantly lower than in cells carrying the risk allele. We show in vitro that SLCO2B1 expression levels correlated with DHEAS uptake by PC cells. CONCLUSION: The association of SNP rs1077858 with OS may be a result of differential SLCO2B1 expression and the consequent increased uptake of DHEAS and subsequent resistance to ADT, which, in turn, may contribute to decreased OS.

The Development of Intermediate Clinical Endpoints in Cancer of the Prostate (ICECaP).

New systemic therapies have prolonged the lives of men with metastatic castration-resistant prostate cancer (mCRPC). Use of these therapies in the adjuvant setting when the disease may be micrometastatic and potentially more sensitive to therapies may decrease mortality from prostate cancer. However, the conduct of adjuvant prostate cancer clinical trials is hampered by taking longer than a decade to reach the meaningful endpoint of overall survival (OS) and the fact that many men never die from prostate cancer, even if they relapse. A validated intermediate clinical endpoint (ICE) in prostate cancer that is a robust surrogate for OS has yet to be defined. This paper details the plans, process, and progress of the international Intermediate Clinical Endpoints in Cancer of the Prostate (ICECaP) working group to pool individual patient data from all available clinical trials of radiation or prostatectomy for localized disease and conduct the requisite analyses to determine whether an ICE can be identified. This paper further details the challenges and the a priori statistical analytical plans and strategies to define an ICE for adjuvant prostate cancer clinical trials. In addition, a brief review of the health economic analyses to model the benefits to patients, society and manufacturers is detailed. If successful, the results from this work will provide a robust surrogate for OS that will expedite the design and conduct of future adjuvant therapy trials using new agents that have proven activity in mCRPC. Moreover, it will also define the health economic benefits to patients and societies.

Statin Use at the Time of Initiation of Androgen Deprivation Therapy and Time to Progression in Patients With Hormone-Sensitive Prostate Cancer.

IMPORTANCE: Statin use has been associated with improved prostate cancer outcomes. Dehydroepiandrosterone sulfate (DHEAS) is a precursor of testosterone and a substrate for SLCO2B1, an organic anionic transporter. We previously demonstrated that genetic variants of SLCO2B1 correlated with time to progression (TTP) during receipt of androgen deprivation therapy (ADT). Statins also use SLCO2B1 to enter cells, and thus we hypothesized that they may compete with DHEAS uptake by the tumor cells. OBJECTIVE: To evaluate whether statin use prolongs TTP during ADT for hormone-sensitive prostate cancer. DESIGN, SETTING, AND PARTICIPANTS: In vitro studies were performed using prostate cancer cell lines at an academic, comprehensive cancer center. Statin use was retrospectively analyzed in 926 patients who had received ADT for biochemical or metastatic recurrence or de novo metastatic prostate cancer between January 1996 and November 2013. MAIN OUTCOMES AND MEASURES: To determine whether statins interfere with DHEAS uptake, we performed in vitro studies using prostate cancer cell lines. Next, we queried our institutional clinical database to assess for an association between statin use and TTP during ADT using multivariable Cox regression analysis and adjusted for known prognostic factors. RESULTS: In vitro, we demonstrated that statins block DHEAS uptake by competitively binding to SLCO2B1. In our ADT cohort of 926 patients, 283 (31%) were taking a statin at ADT initiation. After a median follow-up of 5.8 years, 644 patients (70%) had experienced disease progression while receiving ADT. Median TTP during ADT was 20.3 months (95% CI, 18-24 months). Men taking statins had a longer median TTP during ADT compared with nonusers (27.5 [95% CI, 21.1-37.7] vs 17.4 [95% CI, 14.9-21.1] months; P < .001). The association remained statistically significant after adjusting for predefined prognostic factors (adjusted hazard ratio, 0.83 [95% CI, 0.69-0.99]; P = .04). The positive statin effect was observed for both patients with and without metastases (adjusted hazard ratio, 0.79 [95% CI, 0.58-1.07] for M0 disease and 0.84 [95% CI, 0.67-1.06] for M1 disease; P for interaction = .72). CONCLUSIONS AND RELEVANCE: Statin use at the time of ADT initiation was associated with a significantly longer TTP during ADT even after adjustment for known prognostic factors. Our in vitro finding that statins competitively reduce DHEAS uptake, thus effectively decreasing the available intratumoral androgen pool, affords a plausible mechanism to support the clinical observation of prolonged TTP in statin users.

Patients with Biopsy Gleason 9 and 10 Prostate Cancer Have Significantly Worse Outcomes Compared to Patients with Gleason 8 Disease.

PURPOSE: We examined differences in outcome in patients with biopsy Gleason score 8 vs 9-10 who received definitive local therapy. MATERIALS AND METHODS: Using an institutional database we identified a cohort of 847 patients with biopsy Gleason 8-10 disease who received definitive local therapy with radiation therapy or radical prostatectomy between January 2001 and December 2011. Multivariable Cox modeling was used to assess the association of Gleason score 8 vs 9-10 with time to biochemical recurrence, metastasis and overall survival, and evaluate treatment by Gleason score interaction. Median followup in the cohort was 5.3 years. RESULTS: Baseline patient characteristics were similar for biopsy Gleason 8 vs 9-10. Gleason 9-10 disease was associated with higher prostate specific antigen at diagnosis. As local treatment such patients were also more likely to have received radiation therapy (58% vs 46%, p = 0.001) and neoadjuvant/adjuvant androgen deprivation therapy (64% vs 49%, p <0.001). Those with higher grade disease were at increased risk for metastasis (HR 1.41, 95% CI 1.11-1.79). There was a trend toward an increased risk of death in Gleason 9-10 vs 8 cases (HR 1.28, 95% CI 0.98-1.66). The increased risk of death for Gleason 9-10 was mainly observed in patients treated with radical prostatectomy with or without additional radiation therapy (HR 1.74, 95% CI 1.15-2.65). CONCLUSIONS: Patients with localized biopsy Gleason 9-10 disease treated with definitive local therapy had worse outcomes than those diagnosed with biopsy Gleason 8 disease. Clinical trials are urgently needed that incorporate newer approaches to Gleason 9-10 cancer.

Role of androgen deprivation therapy in early salvage radiation among patients with prostate-specific antigen level of 0.5 or less.

BACKGROUND: The Radiation Therapy Oncology Group 96-01 randomized trial demonstrated the benefit of adding androgen deprivation therapy (ADT) to salvage radiotherapy for an increasing prostate-specific antigen (PSA) after prostatectomy, but it is unknown whether modern patients followed with ultrasensitive PSA and salvaged at a low PSA (ie, ≤ 0.5) also benefit from ADT. PATIENTS AND METHODS: The cohort comprised 108 patients who received radical prostatectomy (RP), were followed by ultrasensitive PSA, and received salvage radiotherapy at a PSA of 0.5 or less. Sixty patients had negative margins, and 48 patients had positive margins at RP. Cox multivariable regression analysis was performed to identify factors associated with time to secondary PSA failure and included PSA at salvage, year of treatment, Gleason score, ADT use, margin status, T stage, and PSA doubling time. Occurrence of distant metastases was documented. RESULTS: Median follow-up after radiation was 63.09 months. A total of 24 patients had a distant metastasis. In all patients, ADT use was associated with a decreased risk of recurrence (hazard ratio [HR], 0.44; 95% confidence interval [CI], 0.25-0.79; P = .006). On subgroup analysis, ADT was associated with a decreased risk of failure among patients with negative margins (HR, 0.27; 95% CI, 0.12-0.61; P = .002), but not among men with positive margins (HR, 0.78; 95% CI, 0.29-2.10; P = .63). CONCLUSIONS: Even patients followed with ultrasensitive PSA and salvaged early with a PSA ≤ 0.5 seem to benefit from the addition of ADT to salvage radiation. However, this benefit seemed to be limited to men with negative margins; thus, men with positive margins and PSA ≤ 0.5 may be good candidates for salvage radiation alone.

Whole-exome sequencing of circulating tumor cells provides a window into metastatic prostate cancer.

Comprehensive analyses of cancer genomes promise to inform prognoses and precise cancer treatments. A major barrier, however, is inaccessibility of metastatic tissue. A potential solution is to characterize circulating tumor cells (CTCs), but this requires overcoming the challenges of isolating rare cells and sequencing low-input material. Here we report an integrated process to isolate, qualify and sequence whole exomes of CTCs with high fidelity using a census-based sequencing strategy. Power calculations suggest that mapping of >99.995% of the standard exome is possible in CTCs. We validated our process in two patients with prostate cancer, including one for whom we sequenced CTCs, a lymph node metastasis and nine cores of the primary tumor. Fifty-one of 73 CTC mutations (70%) were present in matched tissue. Moreover, we identified 10 early trunk and 56 metastatic trunk mutations in the non-CTC tumor samples and found 90% and 73% of these mutations, respectively, in CTC exomes. This study establishes a foundation for CTC genomics in the clinic.

Elevated IL-8, TNF-α, and MCP-1 in men with metastatic prostate cancer starting androgen-deprivation therapy (ADT) are associated with shorter time to castration-resistance and overall survival.

BACKGROUND: Chemokines and cytokines have been implicated in progression to castration-resistant prostate cancer (CRPC). METHODS: Retrospective data were accessed from 122 men with serum samples drawn at a median of 0.5 months after starting ADT for metastatic prostate cancer. MCP-1, IL-1-ß, IL-2, IL-8, IL-6, and TNF-α levels were measured by multiplex electrochemiluminescence assays. A multivariable Cox model assessed the association of time to CRPC and overall survival by the protein levels and adjusted for clinical variables (age and prostate specific antigen (PSA) levels at start of ADT, race, ECOG status, and extent of metastases). Associations were reported as hazard ratio (HR) with 95% confidence interval (CI). RESULTS: Median follow-up and overall survival were 44 and 42.2 months, respectively. ECOG performance status (≥1 vs. 0) was negatively associated with overall survival [HR = 2.8 (1.1-7.0), P = 0.03], and PSA nadir < 0.2 was predictive of longer time to development of CRPC [HR = 0.3 (0.2-0.5), P < 0.0001]. The HR for time to CRPC by protein above the median was 1.4 (95% CI: 0.9, 2.2, P = 0.13) for IL-8; 1.3 (95% CI: 0.8, 2, P = 0.18) for TNF-α; 1.0 (95% CI: 0.7, 1.6, P = 0.95) for MCP-1. The HR for median overall survival for protein levels above the median was: 1.9 (95% CI: 1.0, 3.5, P = 0.04) for IL-8; 2.0 (95% CI: 1.1, 3.5, P = 0.02) for TNF-α; 1.7 (95% CI: 1.7, 3.0, P = 0.08) for MCP-1. There was no association with IL-1-ß, IL-2, or IL-6. CONCLUSION: Higher levels of inflammation-associated cytokines correlate with poorer prostate cancer outcomes and may guide strategies to improve prostate cancer therapy.

Functional analysis of single cells identifies a rare subset of circulating tumor cells with malignant traits.

Ample evidence supports genetic and functional heterogeneity in primary tumors, but it remains unclear whether circulating tumor cells (CTCs) also exhibit the same hierarchical organization. We examined the functional diversity of viable, single CTCs using an array of subnanoliter wells (nanowells). The compartmentalization of single cells by nanowells allowed clonal comparison and mapping of heterogeneity of single cells or preformed clusters of cells. By measuring the short-term viability, invasiveness and secretory profiles of individual CTCs, it was evident that only a rare subset of CTCs possessed malignant traits indicative of metastatic potential in late-stage, progressing metastatic castration-resistant prostate cancer (mCRPC) patients. These CTCs were resistant to anoikis after being in the circulation, were invasive in their epithelial state, or secreted proteases capable of cleaving peptide substrates. Every CTC observed, however, did not exhibit such metastatic potential, suggesting that enumeration of CTCs alone may be insufficient to understand metastasis or stratify patients.

Elevated insulin-like growth factor binding protein-1 (IGFBP-1) in men with metastatic prostate cancer starting androgen deprivation therapy (ADT) is associated with shorter time to castration resistance and overall survival.

BACKGROUND: Insulin-like growth factor (IGF) and adipokines have been implicated in prostate cancer carcinogenesis. METHOD: Data from 122 men with serum samples drawn within 3 months of starting ADT for metastatic prostate cancer was accessed retrospectively. IGF-1, IGF binding protein (BP)-1, leptin, and adiponectin levels were measured by multiplex electrochemiluminescence assays. A multivariable Cox model assessed the association of time to castration resistant prostate cancer (CRPC) and overall survival by the protein levels, adjusted for clinical variables, age and prostate specific antigen (PSA) levels at start of ADT, race, ECOG status, extent of metastases and were reported as hazard ratio (HR) with 95% confidence interval (CI). RESULTS: Median follow-up and overall survival were 44 and 42.2 months, respectively. ECOG performance status (≥ 1 vs. 0) was negatively associated with overall survival [H = 2.8 (1.1-7.0), P = 0.03], and PSA nadir <0.2 was predictive of longer time to CRPC [HR = 0.3 (0.2-0.5), P < 0.0001]. The median time to CRPC by low, middle, and top IGFBP-1 tertile distribution was 20.7, 18.1, and 12.4 months, respectively, with HR for middle versus low tertile levels 3.1 (1.7-5), P = 0.0003, and for top versus low tertile levels was 2.4 (1.3-4.2), P = 0.003. The median overall survival by low, middle and top tertile IGFBP-1 level was 48.5, 46.4, and 32.8 months, respectively, with HR for top versus low tertile 2.5 (1.2-5.1), P = 0.01. There was no association with IGF-1, adiponectin and leptin. CONCLUSION: Elevated IGFBP-1 appears to be associated with shorter time to CRPC and lower overall survival in men with metastatic prostate cancer.

Clinical predictors of survival in men with castration-resistant prostate cancer: evidence that Gleason score 6 cancer can evolve to lethal disease.

BACKGROUND: This study sought to characterize Modern patients with castration-resistant prostate cancer (CRPC) and identify pretreatment clinical predictors of survival. METHODS: A cohort of men with CRPC with and without metastases (M) treated with secondary hormonal therapy (2eHT) and/or chemotherapy (CT) was identified from the authors' institutional database. Associations of patient and disease characteristics at diagnosis, at androgen-deprivation therapy (ADT) initiation, at CRPC index date, and survival were evaluated. CRPC index date was defined as the start date of either 2eHT or CT, whichever came first. RESULTS: In the cohort of 622 men, 434 men (70%) had M-positive disease; 552 men (89%) received 2eHT and 70 men (11%) received CT as their initial CRPC treatment. There were 410 deaths (66%) at the time of analysis. Median overall survival (OS) was 35 months (quartile 1, quartile 3: 21 months, 61 months). In multivariate analyses, higher biopsy Gleason score, the presence of M at ADT initiation, shorter time from ADT start to CRPC, higher prostate-specific antigen and poorer Eastern Cooperative Oncology Group performance status at CRPC and M at CRPC were predictive of shorter OS. Interestingly, whereas some men with biopsy Gleason scores of 6 died of their disease (N = 42), they had a longer OS after CRPC compared with those with a Gleason score ≥ 7. CONCLUSIONS: This large retrospective study of patients with CRPC in a tertiary cancer center shows that biopsy Gleason score of 6 is associated with a less aggressive CRPC course, and the impact that M at ADT initiation and CRPC have on outcome is quantified.

Long-term follow-up of a phase II trial of chemotherapy plus hormone therapy for biochemical relapse after definitive local therapy for prostate cancer.

OBJECTIVE: To evaluate long-term follow-up of a phase II trial of chemohormonal therapy in 62 men with prostate cancer biochemical relapse (BR). METHODS: Treatment was 4 cycles of docetaxel (70 mg/m(2)) every 3 weeks and estramustine 280 mg three times a day (days 1-5) followed by 15 months of goserelin acetate/bicalutamide. The primary endpoint was the proportion with prostate-specific antigen (PSA) <0.1 with recovered testosterone 5 years after completion of therapy. Secondary endpoints included time to progression (TTP), time to reinitiate androgen deprivation therapy (ADT), the proportion with castration-resistant prostate cancer (CRPC), and overall survival (OS). RESULTS: Median follow-up was 8.6 years (range 1.3-11.1 years). At 5 year follow-up, 7 patients (11%) had PSA <0.1 (5 undetectable); 8 (13%) had PSA >0.1 but without reinitiation of ADT (median PSA 0.37). Of the 15 (24%) men without reinitiation of ADT, and 14 have recovered testosterone to normal range. Median TTP for the complete cohort was 35.0 months (95% confidence interval [CI] 31.7-39.2). Baseline PSA <3.0 ng/dL, no prior ADT, and prostatectomy (vs radiation) were associated with longer TTP (P = .0001, P = .0055, and P = .0398, respectively). At the time of analysis, 42 men (68%) had restarted ADT, 23 men had CRPC (37%), and 11 (18%) had chemotherapy. Median time to reinitiation of ADT was 32.6 months (range 0-107.6 months). Median OS has not been reached; there were 15 deaths. CONCLUSION: Chemotherapy plus ADT for BR resulted in durable (>5 years) complete responses (<0.1 ng/mL) in 7 men (11%). Twenty-four percent of men have not re-initiated ADT 5 years from completion of protocol therapy.

Phase II trial of RAD001 and bicalutamide for castration-resistant prostate cancer.

UNLABELLED: Study Type--Therapy (cohort) Level of Evidence 2a. What's known on the subject? and What does the study add? Despite expanding treatment options for castration-resistant prostate cancer (CRPC), therapies with long response duration remain intangible due to prostate cancer cells' natural ability to develop iterative resistance. Androgen receptor (AR) signaling has been shown to play a critical role in CRPC and its expression is regulated by the PI3K-Akt pathway. Thus inhibition of AR signalling and PI3K-Akt-mTOR (a downstream mediator of the PI3K-Akt pathway) pathway is a logical combination in CRPC and we report a phase II trial of RAD001 and bicalutamide. Our study is the first clinical trial report of an AR inhibitor of PI3K-Akt-mTOR. The AR pathway and the PI3K-Akt-mTOR pathway are two of the most relevant growth pathway for CRPC. Despite low efficacy results from our trial there will be significant interest in the field for these data (dose, schedule, response, toxicity, trial design) as newer generations of both AR inhibitors and PI3K-Akt-mTOR inhibitors are in development and likely will be tested in combination in CRPC. OBJECTIVES: • To determine best overall response and duration of response of RAD001, a selective inhibitor of mammalian target of rapamycin, in combination with bicalutamide in castration-resistant prostate cancer (CRPC). • To characterize the toxicity profile of RAD001 in combination with bicalutamide in patients with CRPC. PATIENTS AND METHODS: • A phase II study was conducted to explore the efficacy and tolerability of RAD001 (10 mg daily) in combination with bicalutamide (50 mg daily) in men with progressive CRPC. • The primary endpoint was a composite of prostate-specific antigen (PSA) level and measurable disease response by standard criteria. • This single-stage trial with a sample size of 38 eligible patients provided 90% power to differentiate a response rate of ≥ 40% from a response rate of ≤ 20%, as expected for bicalutamide alone (α= 0.10, power = 0.90). RESULTS: • In total, 36 men were enrolled, with a median (range) age of 68 (60-72) years and median (range) baseline PSA level of 22.2 (8.4-121.3) ng/mL, and 89% had metastatic disease. • There were 31 (86%) patients had previously used bicalutamide for a median duration of 7.4 months. • There were two patients with a confirmed PSA level decline ≥ 50%. • The median (interquartile range) time to progression was 8.7 (7.9-15.9) weeks. • The most common toxicity was grade 1/2 mucositis, which was observed in 20 (56%) patients. CONCLUSION: • The combination of RAD001 and bicalutamide in men with CRPC was well tolerated but had low activity and failed to achieve the primary endpoint of improved response compared to the results previously achieved for bicalutamide alone in this population.

Secondary hormonal therapy in men with castration-resistant prostate cancer.

BACKGROUND: Androgen receptor (AR) signaling remains important in castration-resistant prostate cancer (CRPC) and sequential responses to hormonal therapies are observed. Little is known about the factors associated with responsiveness to secondary hormone therapy (HT). METHODS: We retrospectively identified patients with CRPC who were treated with secondary HT. Patient characteristics and types and duration of secondary HT were analyzed. Selected clinical characteristics and their association with duration of secondary HT were evaluated. RESULTS: Of 436 eligible patients, 321 (74%) and 87 (20%) received at least two or four secondary HT regimens, respectively. Median duration of time on primary androgen deprivation therapy alone (ADT) and secondary HT were 24.0 months (range, 1.5 to 171.8 months) and 30.3 months (range, 0.6 to 156.1+ months), respectively. Patients who received primary ADT ≥ 24 months received secondary HT for a median duration of 40.0 months, whereas men who received ADT < 24 months had a median duration of 18.4 months on secondary HT (P < .0001). Metastatic disease at secondary HT initiation was associated with a shorter time on secondary HT (P = .0001). Patients who received the first secondary HT for ≥ 6 months were more likely to have a longer duration on subsequent secondary HT compared with the men who received the first secondary HT < 6 months (P = .0001). CONCLUSIONS: Treatment durations of secondary HT are variable. Longer duration of primary ADT was associated with longer duration of secondary HT. These results imply that AR signaling remains an important therapeutic target in CRPC.